Drop Python 3.9 support

.github/workflows/ci.yml

@@ -22,7 +22,6 @@ jobs:
       fail-fast: false
       matrix:
         python-version:
-          - "3.9"
           - "3.10"
           - "3.11"
           - "3.12"

HACKING.txt

@@ -62,7 +62,7 @@ Tests
 **nagiosplugin** tests are run by `tox`_ using the versions locked in
 ``uv.lock``. Install all supported Python versions with `uv`::
 
-   uv python install 3.9 3.10 3.11 3.12 3.13
+   uv python install 3.10 3.11 3.12 3.13
 
 Install test dependencies::
 
@@ -75,15 +75,11 @@ The dependency lock contains temporary constraints which preserve the full
 runtime test matrix without making development tools part of the package's
 runtime requirements:
 
-- The ``test`` group selects ``pytest<9`` on Python 3.9 and ``pytest>=9`` on
-  newer interpreters because pytest 9 requires Python 3.10 or later. Replace
-  these marked requirements with an unconstrained ``pytest`` requirement when
-  Python 3.9 support is dropped.
 - The ``docs``, ``dev``, ``lint``, and ``security`` groups declare Python 3.11
   or later in ``[tool.uv.dependency-groups]``. These declarations prevent
-  tooling that has dropped Python 3.9 or 3.10 from narrowing nagiosplugin's
-  runtime support. They become redundant and may be removed when the package's
-  minimum supported Python version reaches 3.11.
+  tooling that has dropped Python 3.10 from narrowing nagiosplugin's runtime
+  support. They become redundant and may be removed when the package's minimum
+  supported Python version reaches 3.11.
 
 After doing so, run the unit tests::
 

README.txt

@@ -20,7 +20,7 @@ and default logic commonly found in Nagios checks, including:
 - No dependencies beyond the Python standard library (except for Python 2.6).
 
 **nagiosplugin** runs on POSIX and Windows systems. It is compatible with
-and Python 3.9 and later.
+Python 3.10 and later.
 
 Feedback and Suggestions
 ------------------------

pyproject.toml

@@ -14,15 +14,14 @@ maintainers = [
 readme = "README.txt"
 license = { text = "ZPL-2.1" }
 keywords = ["Nagios", "Icinga", "plugin", "check", "monitoring"]
-requires-python = ">= 3.9"
+requires-python = ">= 3.10"
 classifiers = [
     'Development Status :: 5 - Production/Stable',
     'Environment :: Plugins',
     'Intended Audience :: Developers',
     'Intended Audience :: System Administrators',
     'Operating System :: Microsoft :: Windows',
     'Operating System :: POSIX',
-    'Programming Language :: Python :: 3.9',
     'Programming Language :: Python :: 3.10',
     'Programming Language :: Python :: 3.11',
     'Programming Language :: Python :: 3.12',
@@ -97,9 +96,7 @@ security = [
     "pip-audit",
 ]
 test = [
-    # pytest 9 requires Python 3.10, but the test matrix still includes 3.9.
-    "pytest<9; python_version < '3.10'",
-    "pytest>=9; python_version >= '3.10'",
+    "pytest>=9.0.3",
     "pytest-cov",
 ]
 
@@ -110,7 +107,7 @@ lint = {requires-python = ">=3.11"}
 security = {requires-python = ">=3.11"}
 
 [tool.pylint]
-py-version=3.9
+py-version=3.10
 
 [tool.pylint."messages control"]
 disable=[
@@ -139,7 +136,7 @@ convention = "pep257"
 [tool.tox]
 envlist = [
     "clean", "bandit", "pip-audit", "ruff", "pylint", "pydocstyle",
-    "py39", "py310", "py311", "py312", "py313",
+    "py310", "py311", "py312", "py313",
     "stats"
 ]
 skip_missing_interpreters = false